Hair dryer

ABSTRACT

A hair dryer includes a heater, a fan, a motor for driving the fan, a body case that accommodates the heater, the fan, and the motor, and a thermal barrier tube disposed between the body case and the heater. The diameter of the fan is allowed to be 90 mm or more, and an air quantity formed by the fan is allowed to be 1.0 m 3  to 1.4 m 3 /min, thereby enabling reduction of noise while resulting in the sufficient air quantity.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No.2014-105469, filed on May 21, 2014. The entire specification, claims,and drawings of Japanese Patent Application No. 2014-105469 areincorporated by reference herein.

FIELD

The present disclosure relates to a hair dryer in which air taken in bya fan is heated by a heater. In particular, the present disclosurerelates to a hair dryer capable of providing a sufficient air quantityand of reducing a noise level.

BACKGROUND

In a hair dryer for drying hair and/or the like, a fan is rotated by amotor, and air is taken into the main body of the hair dryer through anair suction port, heated by a heater, and discharged out of the mainbody through an air discharge port. Driving of such a hair dryer hasbeen able to generate a noise of 70 dB, to preclude TV or the like frombeing watched or a conversation from being held near the hair dryer, andto disturb the sleep of a sleeping person in the middle of the night.Main causes of the noise of hair dryers are considered to be wind noisecaused by fans, sounds generated by motors, standing wave noise causedby cases, and the like. Although the decreased rotation number of amotor results in the reduced noise of a hair dryer, the excessivelydecreased rotation number prevents an air quantity required by the hairdryer from being obtained.

Many attempts to reduce the noise of hair dryers have beenconventionally made. Unexamined Japanese Patent Application KokaiPublication No. H5-228013 discloses the disclosure in which plural holesare formed at locations having the high axial distributions of the soundpressure of standing wave noise generated by air-column resonance in thecase of a dryer, and a resonator is attached to the outer peripheralsurface of the case so as to cover the holes, to internally form an airlayer, thereby silencing the dryer. According to the constitution of thedisclosure, actuation of a motor causes a blower fan to rotate to resultin generation of an air blow in the case and to spout the air through anoutlet. Noise is generated due to the blow; however, since the pluralholes are formed at the locations having the high axial distributions ofthe sound pressure of the standing wave noise in the case to dispose theresonator on the holes, sounds having specific frequencies can beabsorbed and attenuated to reduce sound pressure. Accordingly, thestanding wave noise generated by air-column resonance can be effectivelyabsorbed to achieve the silence.

Unexamined Japanese Patent Application Kokai Publication No. H6-209818discloses a silent dryer in which a microphone for detecting therotation number of a blower fan, a microphone for monitoring noise in ablowport, and a speaker disposed between the blower fan and themicrophones are connected to a signal processing apparatus andinternally packaged in a main body of the dryer. The signal processingapparatus subjects the output signal of each microphone to phaseinversion and to signal processing in the same amplitude in order toreduce the output signal from each microphone, and sends the processedsignal to the speaker. A sound processed by the signal processingapparatus and output from the speaker, and noise in the blowport havephases reverse to each other, and therefore cancel each other, therebyreducing the noise.

Unexamined Japanese Patent Application Kokai Publication No. H7-265120discloses a hair dryer comprising: a trunk body, of which both side areprovided with a suction port and a discharge port, respectively; acylinder-shaped suction guide placed in the interior of the trunk body;a motor and a fan placed in the interior of the suction guide; and adischarge guide which is placed on the discharge port side of the trunkbody and of which the interior and outlet are provided with a heatingcoil and a discharge nozzle, respectively, wherein a curved surfaceformed at a certain arc angle is elongated and placed from the tip ofthe suction port of the suction guide to spread toward an external side,to regulate the flow of suction air, thereby reducing noise. This hairdryer has the effect of being silently actuated by maintaining the flowof suction air in laminar flow to significantly reduce suction noise.

In the hair dryer of Unexamined Japanese Patent Application KokaiPublication No. H5-228013, there is needed a complicated structure inwhich the plural holes are formed at locations having the high axialdistributions of the sound pressure of standing wave noise generated byair-column resonance in the case, and the resonator is attached to theouter peripheral surface of the case so as to cover the holes.

In the silent dryer of Unexamined Japanese Patent Application KokaiPublication No. H6-209818, it is necessary to dispose the microphones,the speaker, and the signal processing apparatus.

In the hair dryer of Unexamined Japanese Patent Application KokaiPublication No. H7-265120, there is needed a special structure in whichthe curved surface formed at a certain arc angle is elongated and placedfrom the tip of the suction port of the suction guide to spread towardthe external side.

As described above, the conventional hair dryers have been incapable ofreducing noise from the hair dryers unless provided with a specialstructure such as a resonator, a microphone, a speaker, a signalprocessing apparatus, or a curved surface placed on the tip of a suctionport. An objective of the disclosure is to provide a hair dryer in whichnoise can be reduced to 60 dB or less while securing a sufficient airquantity of not less than 1.0 m³/min without allowing the hair dryer tobe provided with a special stricture.

SUMMARY

The problems described above are solved by a hair dryer of the presentdisclosure, including: a heater; a fan; a motor for driving the fan; abody case that accommodates the heater, the fan, and the motor; and athermal barrier tube disposed between the body case and the heater,wherein a diameter of the fan is 90 mm or more, and an air quantityformed by the fan is 1.0 m³ to 1.4 m³/min.

In the hair dryer of the present disclosure, further, the diameter ofthe fan is 105 mm or more, and the air quantity can be 1.2 m³/min orless. As a result, noise from the hair dryer can be allowed to be 53 dBor less.

In the hair dryer of the present disclosure, the diameter of the fan is120 mm, and the air quantity can be 1.0 m³/min. As a result, noise fromthe hair dryer can be allowed to be 43 dB.

In the hair dryer of the present disclosure, a cross-sectional shape ofthe thermal barrier tube can be a streamlined shape. As a result,generated noise can be reduced compared to conventional hair dryers inwhich mica plates have been used.

In the hair dryer of the present disclosure, the thermal barrier tubecan be formed with a heat-resistant resin. As a result, generated noisecan be reduced compared to conventional hair dryers in which mica plateshave been used.

In the hair dryer of the present disclosure, a roll diameter of theheater in an air blow inflow side can be two or more times a rolldiameter of the heater in an air blow outflow side. As a result, atemperature difference depending on a place in which warm air isgenerated can be reduced.

The hair dryer of the present disclosure can include a U-shaped handle.As a result, it becomes easy to hold the hair dryer including the fanhaving a diameter that is as large as 90 mm or more.

In accordance with the hair dryer of the present disclosure, thediameter of the fan is allowed to be 90 mm or more, and the air quantityformed by the fan is allowed to be 1.0 m³ to 1.4 m³/min, therebyenabling achievement of a sufficient air quantity of 1.0 m³/min andenabling noise to be reduced to 60 dB or less without disposing suchspecial structures as disposed in conventional apparatuses. As a result,the need for disposing a special structure is eliminated, and therefore,the manufacturing cost of the hair dryer can be greatly reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of this application can be obtained whenthe following detailed description is considered in conjunction with thefollowing drawings, in which:

FIG. 1 is a longitudinal cross-sectional view of a hair dryer of thepresent disclosure;

FIG. 2 is a plan view of a hair dryer of the present disclosure;

FIG. 3 is a front view of a hair dryer of the present disclosure;

FIG. 4 is a right side view of a hair dryer of the present disclosure;

FIG. 5 is a rear view of a hair dryer of the present disclosure;

FIG. 6 is a bottom view of a hair dryer of the present disclosure;

FIG. 7 is a graph representing a relationship between a fan diameter anda rotation number at an air quantity of 1.2 m³/min; and

FIG. 8 is a graph representing a relationship between a fan diameter anda noise at an air quantity of 1.2 m³/min.

DETAILED DESCRIPTION

A hair dryer 8 of the present disclosure comprises: acylindrically-shaped body case 12; a nozzle 10 disposed in front of thebody case 12; a rear cover 24 disposed behind the body case 12; and ahandle 26 disposed on the top of the body case 12, as illustrated in theplan view (FIG. 2), the front view (FIG. 3), the right side view (FIG.4), the rear view (FIG. 5), and the bottom view (FIG. 6). The handle 26,which has a U shape, facilitates holding of the hair dryer comprising afan having a diameter that is as large as 90 mm or more. When theU-shaped handle is replaced by an L-shaped handle of which only one endis connected to the dryer body, the effect of facilitating holding ofthe hair dryer is also similar. As illustrated in FIG. 2, innumerableholes for taking air in are formed in the rear cover 24.

FIG. 1 is a cross-sectional view illustrating the cross section of thehair dryer 8 taken along the line A-A′ of FIG. 4. A motor 18 is fixed onthe internal side of the body case 12 by nine flow regulating plates 20.A fan 22 is fixed on the surface, facing the rear cover 24, of therotating shaft of the motor 18. The fan 22 comprising seven blades has adiameter of 90 mm or more. A diameter of less than 90 mm, of the fan,results in an insufficient air quantity.

A thermal barrier tube 14 is disposed in front of the flow regulatingplate 20. The winding of a heater 16 is disposed on the internal side ofthe thermal barrier tube 14. The thermal barrier tube 14, which isformed with a heat-resistant resin such as PBT or PPS, has the functionof shielding heat from the heater 16 to prevent the body case 12 frombeing influenced by the heat. A conventional hair dryer has included amica plate (internal side) and a steel plate (external side) ascomponents corresponding to the thermal barrier tube 14; however, themica plate has been vibrated to generate noise by the flow of air. Inthe hair dryer 8 of the present disclosure, such a problem is solved byadopting the thermal barrier tube 14 with a heat-resistant resin. Sincethe inner surface of the thermal barrier tube 14 is formed to have astreamlined shape that is weakly convex toward the internal side, theflow of air is smoothened to reduce the noise generated due to thethermal barrier tube 14. In addition, it has been difficult to alter theshape of a conventional mica plate to be streamlined.

The diameter of the winding of the heater 16 is varied along thedirection of the flow of air. In other words, the roll diameter of theheater 16 in an air inflow side is 93.6 mm while the roll diameter ofthe heater 16 in an air outflow side is 44 mm. The temperature of airheated by the heater 16 varies greatly depending on a place. However,the temperature difference of air was able to be reduced to 25° C.(maximum temperature of 95° C. and minimum temperature of 75° C.) at anair quantity of 1.2 m³/min by adopting such numerical values as the rolldiameters of the heater 16. In a conventional hair dryer, thetemperature difference of air depending on a place was 55° C. (maximumtemperature of 115° C. and minimum temperature of 60° C.) at an airquantity of 1.2 m³/min. Therefore, the temperature difference in thehair dryer 16 of the present disclosure is improved.

The nozzle 10, which is disposed in front of the body case 12, allowsair heated by the heater 16 to converge and to be discharged from thehair dryer 8. It is not essential to dispose the nozzle 10 in the hairdryer 8.

FIG. 7 represents a relationship between the diameter of the fan 22 andthe rotation number of the motor 18 at an air quantity of 1.2 m³/min,and FIG. 8 represents a relationship between the diameter of the fan 22and the noise at an air quantity of 1.2 m³/min.

Table 1 represents a relationship of the diameter of the fan 22, therotation number of the motor 18, and a noise at an air quantity of 1.2m³/min.

TABLE 1 Fan diameter Rotation number Noise (mm) (rpm) (dB) 60 12000 6575 7800 61 90 5400 57 105 4000 53 120 3000 48

As is clear from Table 1 above, at an air quantity of 1.2 m³/min, thenoise is 65 dB when the diameter of the fan 22 is 60 mm, the noise is 61dB when the diameter of the fan 22 is 75 mm, and the noise is 57 dB whenthe diameter of the fan 22 is 90 mm. In other words, it is necessary toallow the fan 22 to have a diameter of 90 mm or more at an air quantityof 1.2 m³/min in order to reduce the noise to 60 dB or less.

Table 2 represents a relationship of the diameter of the fan 22 and thenoises at air quantities of 1.4 m³/min, 1.2 m³/min, and 1.0 m³/min.

TABLE 2 Air Air Air quantity of quantity of quantity of 1.4 1.2 1.0 Fandiameter Noise Noise Noise (mm) (dB) (dB) (dB) 60 67 65 62 75 64 61 5890 60 57 53 105 56 53 48 120 51 48 43

Based on the above, it is necessary to allow the diameter of the fan 22to be 90 to 120 mm in order to allow the noise from the hair dryer 8 tobe 60 dB or less at an air quantity of 1.4 m³/min. In addition, it isnecessary to allow the diameter of the fan 22 to be 90 to 120 mm inorder to allow the noise to be 60 dB or less at an air quantity of 1.2m³/min. In addition, it is necessary to allow the diameter of the fan 22to be 75 to 120 mm in order to allow the noise to be 60 dB or less at anair quantity of 1.0 m³/min. In addition, the noise can be reduced to 43dB when the diameter of the fan 22 is 120 mm. In summary, it is foundthat it is necessary to allow the diameter of the fan 22 to be 90 mm ormore in order to reduce the noise to 60 dB or less while securing asufficient air quantity of 1.0 to 1.4 m³/min.

The foregoing describes some example embodiments for explanatorypurposes. Although the foregoing discussion has presented specificembodiments, persons skilled in the art will recognize that changes maybe made in form and detail without departing from the broader spirit andscope of the invention. Accordingly, the specification and drawings areto be regarded in an illustrative rather than a restrictive sense. Thisdetailed description, therefore, is not to be taken in a limiting sense,and the scope of the invention is defined only by the included claims,along with the full range of equivalents to which such claims areentitled.

What is claimed is:
 1. A hair dryer comprising: a heater; a fan; a motorfor driving the fan; a body case that accommodates the heater, the fan,and the motor; and a thermal barrier tube disposed between the body caseand the heater, wherein a diameter of the fan is 90 mm or more; and anair quantity formed by the fan is 1.0 m³ to 1.4 m³/min.
 2. The hairdryer according to claim 1, wherein the diameter of the fan is 105 mm ormore; and the air quantity is 1.2 m³/min or less.
 3. The hair dryeraccording to claim 2, wherein the diameter of the fan is 120 mm; and theair quantity is 1.0 m³/min.
 4. The hair dryer according to claim 1,wherein a cross-sectional shape of the thermal barrier tube is astreamlined shape.
 5. The hair dryer according to claim 1, wherein thethermal barrier tube is formed with a heat-resistant resin.
 6. The hairdryer according to claim 1, wherein a roll diameter of the heater in anair blow inflow side is two or more times a roll diameter of the heaterin an air blow outflow side.
 7. The hair dryer according to claim 1,comprising a U-shaped handle.